Process of treating mixed sulfid ores.



E. LANGGUTH.

PROCESS OF TREATING MIXED SULFID ORES. APPLICATION FILED SEPT. 11, I913.

1,1 44 A81 0 Patented June 29, 1915.

iulfids of ZiniEead, Silver, [Ironl Treatment with molten zinc chiorid Li gnc suifl'd, lead chi0rid,zinc chiorid,siiverchiorid [Ferrous chioridjTreatment with limited quantity of zinc.

F I sliver-iead. \imc suifuLiead chiorld, zinc chiorrd lgfig gg illTreatment with water.

5oiid I Solution. 7 Zinc chiorid. Lead chiorid. [Ferrous chiorid] M QTreatment with zinc.

S ongy lead. Zinc chiorid.

[Ferrous chioriol] Treatment with Zinc Oxid and Air.

L a I Zinc chiorid. Iron Ox yh drate] WITNESSES lA/I/E/VTOR g 7 0E/P/CHL/i/VGGK/i'fl (WW Enron LANG-.GUTH, or nnnarntr, BELGIUM.

EBOCE SS OF TREATING MIXED SULFID GEES.

llfil ildAldll.

Specification of Letters Patent.

Patented June 29, 11915.

Application filed September 11, 1913. Serial No. 789,344:

To all whom it may concern:

Be it known that I, Enron LANGGUTH, a subject of the King of Prussia,and a resident of Neerpelt, in the Province of Limbourg, Belgium, haveinvented a new and useful and Improved Process of Treating Mixed SulfidOres, of which the following is a specification.

My invention relates to the extraction of silver and lead from mixedoresand especially such as contain lead and silver sulfids; such oresordinarily containing zinc and iron sulfids.

The present invention is built up upon the known'reaction by means ofwhich the silver and lead sulfids are converted into chlorid by theaction of molten zinc chlorid, or its equivalents, such as its doublesalts, upon the mixed sulfids as they exist in the mixed ores. Numerousdifiiculties were encountered in the processes heretofore known inconnection with the economical extraction of silver and lead from thechlorids as they exist as the result of the above treat ment.Electrolytic processes by means of which the metals are recovered havebeen tried: but are ineificient from an economical standpoint. It hasfurther been suggested to separate the fused melt mechanically from thesolid residue, to dissolve it in hot water and recover the silverandlead of the water solution. A great part of the melt Will be retained bythe residues and soluble chlorids contained in this part of the meltmust be extracted by hot water. During this extraction the silverchlorid in the water solution containing zine blends will reconvertitself into the form of an insoluble silver sulfid, leaving zincchlorid. This suggested process accordingly fails to result in a. yieldof silver. In another process the total lead and silver contents werereduced by zinc in the molten mass.

This process was found favorable in some rare cases, but generally agreat excess of zinc was wanted .and a dross was formed which greatlydisturbed the process. I have found that it is the presence of iron inthe ores which has heretofore prevented an economically operativerecovery of silver and lead in this process. The difiiculty created bytheapresence of iron or iron combinations and particularly pyrites isfound in the fact that iron chlorid is reduced to a metallic state bymolten zinc and separates out in the form of a dross which containsiron, zinc, lead and, according to the nature of the ore, also copper,silver and gold. This dross is pulpy or pasty and where the ironconstituent is relatively large, it is not fusible and cannot thereforebe separated from the melt which contains the ore. The reduction of theiron salts takes place after the complete reduction of the silver andsimultaneously with and after the reduction of the last reduced portionsof lead chlorid and it can therefore be avoided entirely by adding thezinc to the melt in limited quantities sufiicient to reduce the silver,and only a part of the lead. In this case no excess of zinc is wanted,as the amount of it corresponds exactly to the reduced quantities oflead and silver, and these metals can be extracted in a condition inwhich they are free from iron while the formation of the deleteriousdross is avoided. The remaining part of lead can be extracted from themelt in any suitable Way after dissolving the melt in hot water andseparating the residues from the solution.

The experiments which I have conducted satisfy me that the priorassertion that lead chlorid is reconverted into sulfid or sulfate by thefinely divided zinc sulfid is incorrect, since the process as abovedescribed by me permits of the separation of the total quantity of leadchlorid even from the finest slimes of zinc sulfid. This correction ofexisting conceptions removed one of the important obstructions to theworking out of a successful process. The lead extracted from a watersolution containing iron salts is free from iron as iron salts are notreduced to a metallic state by zinc in this solution.

' The. process which has been devised to take advantage of theseobservations is briefly the following: The mixed ore is treated withmolten zinc chlorid, or a double salt of zinc and alkali: zinc is thenadded in quantities suflicient to extract the silver and a part of thelead and the molten mass of chlorid remaining, in which all theunaffected constituents of the ore, including the gangue associatedtherewith, are suspended, is poured into water, whereupon the massbreaks up into granules," the water becomes heated andimmediatesolution. of the soluble constituents takes place. Among theseconstituents is lead chlorid. The

solid matter and the liquid matter are now.

zinc oxid. Accordingly, my process enables me not only to render theiron harmless but also to remove it from the salts of the melt so thatthe latter can be -again employed for new operations.

My process is schematically illustrated in the accompanying drawings,the behavior of iron and its extraction, in case this metal is presentin the original ore, being shown in brackets. k

As above explained, the quantlty of lead free from iron that can berecovered from the melt will depend to some degree upon theproportionate amount of iron content in the melt and the degree ofdilution of the lead chlorid in the melt. It is accordingly advisable totest the ores that are to be treated both as to iron and as to leadcontents before the process is started. If it is found that the orecontains a relatively small proportion of lead, the process should becarried out in such a way that no lead at all is precipitated in themelt, but that the total amount of lead is recovered in the watersolution. In this case it is advantageous to add lead to the melt inorder that this may take up the silver that is present, thus formingsilver-lead and lead-chlorid. As the reduction of iron can only takeplace in a molten mass by the action of zinc, anyreduction of iron isprevented in the present process, and the formation of dross and thedisadvantages connected therewith are avoided.

Some of the main advantages of the present process will be found in thefact that it enables the operator to work up mixed sulfids of lead,zinc, and silver in spite of the fact that they contain iron; also thata useless addition of zinc to the melt for the reduction of iron andthe" alloying of zinc with iron is avoided; and finally, that it resultsin a greater degree of. concentration of silver in lead so that the.desilverizing'process is materially cheapened since a large pro ortionofthe lead can be recovered in the 'orm in which it is free from silver.v

and for the purpose described.

2. The .process of treating sulfid ores,

which consists in treating said ores with molten zinc chlorid, adding tothe melt a limited quantity of zinc approximately that required toreduce the silver and only a part of the lead, separating said silverlead from the melt, then pouring the resultant molten mass into waterand then extracting the lead from the solution, substantially as and forthe purpose described. I

3. The process of treating sulfid ores, which consists in treating saidores with molten zinc chlorid, adding to the melt a limited quantity ofzinc approximately that required to reduce the silver and only a part ofthe lead, then pouring the resultant molten mass intowater whereby. theremaining lead constituents of the ore become dissolved, then separatingthe dissolved constituents from the undissolved residue, and thenextracting the lead from the solution, substantially as and for thepurpose described.

4. The process of treating sulfid ores, which consists in treating saidores with molten zinc chlorid, adding to the melt a limited quantity ofzincapproximately that required to reduce the silver and only a part looof the lead, then pouring the resultant required to reduce the silverand only a part of the lead, then pouring the resultant molten mass intowater and then extracting the lead from the solution in form of spongylead by adding zinc thereto, substantially as and for the purposedescribed.

6. The process of treating sulfid ores,

,which consists in treating said ores with molten zinc chlorid, addingto the melt a limited quantity of zinc approximately that required toreduce the silver and only a part In testimony whereof I- have hereuntoset of the lead, then pouring the resultant; my hand in the presence oftwo subscribing molten mass into water and then extracting witnesses.

the lead from the solution and separating .ERICH LANGGUTH. 5 the iron inthe'form of an oxid to purify the Witnesses:

zinc chlorid'so as to render it fit for further ALFRED HINTERLEITNER,

employment in repeating the process. OSCAR DEPNER,

